As many as 150 Tesco lorry drivers have gone on strike over new working terms and conditions.
The dispute arose after the supermarket chain revealed plans to move its depot in Livingston, West Lothian, to a new site nearby.
Local MP Jim Devine called for a one-day boycott of Tesco for threatening to sack drivers who refuse to sign the new contract.
A Tesco spokesman said the chain "strongly refuted" Devine's claims.
The drivers, all members of the Transport and General Workers Union (T&G), are taking part in a strike that is due to last from Thursday until Saturday.
Drivers voted by 126 to six to strike. Tesco strongly refuted claims that the drivers would lose any earnings under the new conditions.
